Safety attachment for punch presses



Aug. 12, 1941. c. c. GOLDBECK SAFETY ATTACHMENT FOR PUNCH PRESSES FiledJune 26, 1940 0. a sauna);

IQIHIIIIHHII Patented Aug. 12, 1941 sAFETYAT'rAoHMENnmR Punch ,7 i. if"-PRESJSES,

Caspar of. Gbldbeck,"Cam'den, N. J. ApplicationJuneZfi, 1940,. SerialNo. 342,570

"5 Claims. (CL-21 92 127) This invention relates to punching -machinesor presses and more=particularly to a safety attachment by means ofwhich the operation of the punch or press maybe stopped-when the diesbecome-clogged withmateriaL.

At the presentitime :in the operation of: punches or presses for formingends of cans,-cons-iderable difficulty is experiencedin-theiaccumulationof punched out material which sticks; in the. moviable :die ,and causesconsiderable damage :noit ionly to the dies *but 'to "the pressqorwm'achine proper. Various safety idevices Eh'ave rloieen' iappliedtothe punches or presses byrmeans'ofwhieh the operating "lever may beshifted .to .stop the machine and While attempts havevheretofore beenmade to provide a safety 'means :to stop themachine when punchedout'endsaccumulate inthe dies, such safety means have-been-of'such a delicatenature that thevibrat-ion of the :punch "or press has a tendency torenderthe safety idevices ineffective. It therefore, an-obj'ect-of thisinvention to provide 'asafetvmeansnof an automatic character which :isoperatively con- 'nected tothe-starting and stopping lever of themachine through the solenoid.leveroperatorat present forming part of"the machine and which is so constructed as to immediately :;stop" theoperation of the machine zafter'not'imore than "two ends are accumulatedin the dies.

Another object of this invention is to provide a safety attachment ofthis kindwhich is connected to the flexible end-engaging member-which ismounted on the movable die and which-flexible member is adapted tostrikeithe ends-'as=they are ireleased from-the dies so as'to'foroe-itheends'to lie flat on the chutezleading from"the dies,zthechute having a means associated with thezflexible end engaging member"for closing a circuit tolthe solenoid leveroperator whenan endis-rnot'discharged from the dies.

A further object of thiszinventi'on is to-provide a safety means of thiskind 'which 'isrsimple'in construction and may be mountedon the presentparts of a punch or press and'which'is not-readily afiected byvibrations of the press or punchiout which-will be positive inits-operation so thatithe dies and the-press or punch apparatus will'not be damaged "by accumulationo'f ends in one or the other of the diesasis at presentthe case.

To the foregoing objects and to others which may hereinafter appear, theinvention consists 0f the novel construction, -combination randaarrangementof parts as will be more specifically referred to andillustrated in theaccompanying -in se'ction {and-partly diagrammatic ofthe "dies of a can end, punch or -press apparatus having a safetyattachment constructed according to this invention connected therewith.

Figure 2 is a plan View of thestationary die and "the discharge chuteshowing themanner of mounting a portion of the safety attachment in thechute.

-;Fi-gure 3%is'a' -bottom plan'of the flexible end engagingmembermemoved from the press and having a portion-of the safetyattachment .rnounted thereon; and I Figurei isa fragmentaryiviewininverted-plan 'of the stripper .Withthe flexible *flapper attachedthereto.

Referring to the :drawing; *the numeral l0 "designates generally-aplunger or-die head'which has mounted thereon a'rnovable die member II.The die member H onits under face is formed with :an annular outercutting edge 42 and 'an annulariend- -forming channel !3. The under or'lower -face-of the die member ll =may also be "formed with'additionalgrooves M depending only 'up'on' the'shape *of' the end which it isdesired to *forrn by 'thedie structure. A substantially stationary orlower die l5is disposed in confrontingrelationto themovabl'e diemember ll and is :formed withcomplementary ribs and grooves Iii .andd'l-whichareadapted to confront the grooves i3 and M andany additional groovesorprojection'swhich are formed 1 in the upper ormovable -die member H.Anz annular cutter'ia is disposed below the movable die! i and ispositioned "about the lower-die member ii. The cutter I8'is stationaryand is secured-to the lower portion H) of "the press; A strippositioning or holding ring eZU'isinterpOsed between'the-cutter if! andthe -'lo'w'erdie member f5 and is adapted to'engage theun'de'r"su-rface' of the strip T-2-l aout if of which the can endsareto-be punched.

A cylindrical or annular end stripper 22 is islidably-disposed about themovable die -=m.ember 4i, being provided at .its upper :edge with an.annular flange .23rformed with openings =24. A plurality of stripperguide rods .or =bc-ltsZ5 are secured to. the head iii and -.-looselyengage through the openings 24 in thewflange .23. A spring "261spositioned about .each'bolt or guide "drawing, wherein =is shown anembodiment :of red-25 and at one end bears againsttheunderside of head land at the other end engages against the upper face of the flange 23 soas to constantly urge the stripper 24 to a stripping or operativeposition with the lower edge of the stripper 22 below the lower cuttingedge |2 or the die The structure hereinbefore described is conventionalin presses or punches and is here disclosed as one type of punch orpress with which the hereinafter described safety attachment may becombined. A chute 21 is disposed on the rear side of the press beingpositioned with the upper edge thereof adjacent the cutter I8 and thechute 21 as shown in Figure 1 is disposed in a downwardly and rearwardlyinclined position so as guide the punched material into a suitablereceptacle or other conveying means. The chute 21 comprises an inclinedbottom wall 28 and upstanding side flanges 29. At the present time whenthe ends punched out by the two dies H and I fall onto the upper surfaceof the chute 21, these ends are forced to assume a flat position withrespect to the chute 21 by means of a flexible member 39. This flexiblemember 30 is formed of leather or other suitable flexible material andone end of the flapper or end engaging member 30 is fixed relative tothe flange 23 of the stripper 22 as shown in Figure 4 so that theflapper 3!! will be disposed in a position overlying the chute 21 and ina position extending lengthwise of the chute 21.

At the present time the press or punch structure is started and stoppedby means of an operating lever 3| which is positioned at one side of themachine and also associated with the operating lever 3| is a solenoidstructure 32. This solenoid structure 32 is at present connected tovarious portions of the press or punch so as to shift the lever 3| to astopping position in the event undesirable conditions exist in theseveral parts of the machine. The solenoid 3| is connected to a suitablesource of electric current supply and is normally inactive, beingrendered active upon operation of one or more of the several safetydevices connected therewith.

In order to provide a means whereby the solenoid 32 may be renderedactive when the die member H is operating and when one or more of theends cut from the supply strip 2| stick in the recesses of the die II, Ihave provided a switch structure including a flexible metal strip Thisstrip 33 is formed with a downwardly arched or arcuate portion 34 and astraight portion 35 which is secured as by a bolt 35 to the under sideof the flapper or flexible member 30. The opposite end 31 of the switchmember 33 is free and slidably engages the under face of the flexiblemember 3|] adjacent the free end thereof. The bolt 36 not onlyconstitutes a means for holding the flexible member 33 on the flexiblestrip 3!] but also constitutes a terminal by means of which a conductor38 may be connected to the switch member 33. The conductor 38 may beconnected to a portion of the press or machine to form a ground whichground is connected as This contact member 40 is connected by means of aconductor 4| to the electric current supply source which is connected tothe solenoid 32 so that when the switch member 33 engages at contact 40a circuit will be completed to the solenoid 32. As shown in Figure l,the contact member 40 is positioned slightly below the upper surface ofthe bottom wall 28 of the chute 21 so that when an end lies flat on theupper surface of the bottom wall 28 and the flexible member 3|) isflexed downwardly, the electric circuit to the solenoid 32 will not becompleted through the end engaging over the slot 39.

However, in the event one or more of the can ends should stick in thedie H, the flapper or flexible member 30 will flex downwardly toward thechute 21 and due to the fact that there is no end moving downwardly andrearwardly from the dies II and I5, the switch member 33 will projectthrough the slot 39 and contact with the contact member 40 and thusclose the electric circuit to the solenoid 32 and effect movement of theoperating lever 3| to a stopping position.

In the normal operation of the punch or press, the head II] with the dieI is moved in the'direction of the lower substantially stationary die l5and the supply sheet 2| is shifted by well known means relative to thedies II and I5. The die H is adapted to cut off an end 2| and this endis formed of a suitable configuration depending upon the configurationof the confronting faces of the two dies II and I5.

At the present time considerable difiiculty is experienced by reason ofthe fact that the ends 2P accumulate in the upper die II and theseaccumulated ends cause considerable damage to result both to the die IIand to the entire press or punch apparatus. After the machine has beenin operation the reciprocation of the head It! is suflicient to causethe flexible member 39 to be flexed downwardly and strike the bottomwall 23 of the chute 21 for the purpose of causing the cut ends to lieflat on the chute 21 and slide downwardly into a receptacle or conveyorat the lower end of the chute.

In the event one or more of the ends should stick in the die H orotherwise not be discharged onto the chute 21, the flexible member 3!]will nevertheless be flexed downwardly toward the chute 21. In theabsence of an end which may be engaged by the flexible member 3!], theswitch member 33 will engage within the slot 33 and contact with thestationary contact 40 so as to thereby close the electric circuit to thesolenoid 32.

losing of the circuit to the solenoid 32 will effect movement of theoperating lever 3| to a stopping position.

With an attachment of this kind the press or punch will be automaticallystopped when not more than two ends have accumulated in the die member Hand these ends may then be removed from the die II and machine operatedin the usual manner. The accumulation of two ends in the die II will notbe sufficient to cause any material damage to result to the dies II and|5 or to the machine proper so that an attachment of this kind willprovide an effective means for preventing damage to the machine in theevent the ends are not discharged into the chute 21 in the normalmanner. This switch device may be mounted on the present parts of apositioning machine or press, it only being necessary to form an opening39 in the chute 21 so that the contact member 49 may be attached to theunderside of the chute 21 within the opening 39. The switch member 33may be secured to the flapper or end engaging member 30 and connected tothe present lever operating solenoid which now forms a part of amachine. A device of this kind has been placed in actual operation andhas been found to be more efficient than devices heretofore availableparticularly in view of the fact that this device is not affected byvibrations of the machine so that the device will not get out of orderby such vibrations. In addition the safety attachment is of anexceedingly simple character embodying a small number of parts so thatthe safety device will not materially increase the cost of the punchingmachine or press.

It will be understood that when the starter lever 3| is initiallyshifted to start up the machine or press, the solenoid 32 isdisconnected from the electric supply source by means of a cut-01fswitch 42 which is connected to one side of the supply source. When thepress begins to run and the punched material moves through the machinethe solenoid is connected to the electric supply source by means of themanually operated switch 42 so that if the material does not moveregularly from the dies, the circuit closer 33 will contact thestationary switch member 40 and energize the solenoid 32 and effectmovement of the operating lever 3| to a machine stopping position.

What I claim is:

1. A safety attachment for a punching machine having a movable die, astationary die and a discharge chute for the formed article, saidattachment comprising a flexible member adapted to be operativelyconnected at one end with said movable die, a switch member carried bysaid flexible member, and a contact below the upper surface of the chutein a position for engagement with said switch member when the chute isfree of a formed article.

2. In combination a punching machine comprising a movable die, astationary die, a discharge chute extending downwardly and rearwardlyfrom said stationary die for guiding a formed article, a starting andstopping lever for causing actuation of said movable die, a solenoidconnected to said lever and adapted upon energization thereof to shiftsaid lever to a stopping position, a switch member movable with saidmovable die and connected to one ide of said solenoid and a contactfixed relative to said chute in a position for engagement with switchmember to thereby close a circuit to said solenoid when the chute isfree of a formed article,

3. In combination a punching machine comprising a stationary die, amovable die, a discharge chute inclined downwardly from said stationarydie for guiding the punched material away from said dies, said chutehaving an opening therein, a flexible member fixed at one end relativeto said movable die and adapted upon downward movement of said movabledie to flex toward said opening in said chute, a rockable operatinglever for causing actuation of said movable die, a solenoid connected tosaid lever for shifting said lever to a stopping position, a contactdisposed in said opening of said chute and positioned below the upperface of the chute bottom, a switch member carried by said flexiblemember in a position to engage said contact when an article punched outby said dies sticks within one of said dies, said switch member beingconnected to said solenoid to thereby close a circuit to the latter forshifting the lever to a stopping position upon the sticking of thearticle.

4. In a punching machine having a stationary die, a movable die, astarting and stopping lever, a lever shifting solenoid for shifting saidlever to a stopping position, a discharge chute for the formed articleand a flexible article striking member, carried by said movable die forflatwise positioning the article in the chute; a safety attachment forenergizing said solenoid upon failure of the article to slide downwardlyof said chute, including a circuit making and breaking means connectedto said solenoid and carried partly by said flexible member and partlyarranged below said chute.

5. In a punching machine having a starting and stopping lever, asolenoid connected to said lever for shifting said lever to a stoppingposition, a pair of material punching dies and a discharge chute leadingfrom said dies; a safety attachment for energizing said solenoid when anarticle fails to move over said chute, said attachment including astationary switch part fixed relative to said chute, a movable switchpart correlated with said stationary part, said movable part beingconnected with said solenoid, and means swing-ably mounting said movablepart for movement with one of said dies.

CASPAR C. GOLDBECK.

